8.1.1 Formation of the Solar System

• The widely accepted explanation for the formation of our solar system is called the Nebula
• A protoplanetary disk surrounds the protostar in the Nebula Theory.

  True
• Steps in the formation of a protosun according to the Nebula Theory

  1️⃣ Gravitational collapse of a molecular cloud

  2️⃣ Formation of a protostar at the center

  3️⃣ Creation of a protoplanetary disk

  4️⃣ Protostar begins to heat up and becomes an early sun
• The remaining gas and dust in the molecular cloud forms a protoplanetary
• In the protoplanetary disk, dust grains collide and stick together through gravity and electrostatic forces in a process called accretion
• The solar system is divided into inner and outer zones with different planetary compositions.

  True
• The outer planets are primarily composed of hydrogen and helium
• What is the first step in the Nebula Theory for the formation of the solar system?

  Gravitational collapse
• In the protoplanetary disk, matter gathers through gravity in a process called accretion
• What is the precursor to our sun called in the Nebula Theory?

  Protostar
• The protosun eventually undergoes nuclear fusion to become the Sun.

  True
• What are small bodies formed by the accretion of dust grains in the Nebula Theory?

  Planetesimals
• Which volatile gases could not condense into solids near the protosun, leading to the formation of rocky inner planets?

  Hydrogen and helium
• Match the feature with the type of planet it describes:

  Rocky composition ↔️ Inner planets

  Gaseous composition ↔️ Outer planets
• The remaining gas and dust in the molecular cloud forms a protoplanetary disk
• In the Nebula Theory, dust grains collide and stick together through electrostatic forces and gravity
• Protoplanets are formed by merging planetesimals.


  True
• Near the protosun, high temperatures prevented volatile gases from condensing
• What is the main difference between major and minor celestial bodies?

  Size and gravitational influence
• The collapse of the giant molecular cloud occurred approximately 4.6 billion years ago, leading to the formation of the protosun
• The disk-shaped structure observed around young stars supports the existence of protoplanetary disks
• Planets' co-planar orbits support the Nebula Theory's idea that they formed from the same disk.


  True
• What is the age of the solar system as determined by meteorite age dating?

  ~4.5 billion years
• The composition gradient within the protoplanetary disk explains why inner planets are rocky and outer planets are gaseous
• What is the protostar stage in the formation of the Sun called?

  Otostar
• Steps in the formation of a protosun

  1️⃣ Gravitational Collapse

  2️⃣ Protostar Formation

  3️⃣ Protoplanetary Disk

  4️⃣ Accretion
• Phases in the accretion of planetesimals

  1️⃣ Dust Grains

  2️⃣ Planetesimals

  3️⃣ Protoplanets
• What is the primary difference in the formation of inner versus outer planets?

  Temperature and materials
• Outer planets have thick atmospheres of hydrogen and helium.


  True
• Match the type of celestial body with its example:

  Major Celestial Body ↔️ Sun

  Minor Celestial Body ↔️ Asteroid
• Timeline of solar system development

  1️⃣ Collapse of Giant Molecular Cloud

  2️⃣ Formation of Protoplanetary Disk

  3️⃣ Accretion of Planetesimals

  4️⃣ Formation of Inner and Outer Planets

  5️⃣ Late Heavy Bombardment

  6️⃣ Solar System Stabilizes
• What event reshaped planetary surfaces around 3.5 billion years ago?

  Late Heavy Bombardment